WASHINGTON — Some census business remains unfinished in the San Joaquin Valley, even as officials prepare to reveal which states will win and which will lose in Congress.

On Tuesday, Census Bureau officials will disclose how the latest U.S. head count reapportions power in the House of Representatives. With some states gaining House seats and others losing them, the decision is among the decade's most politically charged.

Below the radar, meanwhile, investigators are still looking into multiple complaints filed by former Fresno-area Census Bureau workers. Some former workers are considering lawsuits, over allegations that include questions about census accuracy.

"I am concerned with the numbers used for redistricting because of the discrepancies in the collected data," former Fresno-area census worker Robin Walker said in an interview. "This was a strong concern voiced by not only crew leaders and enumerators, but those responsible for the accounting of lost or misplaced data."

Census accuracy is crucial, and Census Bureau officials strongly defend the agency's work. The results are used for everything from rearranging the 435 seats in the House of Representatives to distributing federal dollars.

On Tuesday, for instance, high-growth states including Washington, Florida and Texas are widely expected to gain House seats, while Rust Belt states including Ohio, Michigan and Pennsylvania are expected to lose them.

California, with a population now estimated at 37.4 million, appears likely to retain its current 53 congressional districts.

The shape of individual California districts will be determined next year, by a new 14-member Citizens Redistricting Commission.

Six House districts currently include all or part of the region between Stockton and Bakersfield. Potentially, that could increase to seven. The Rose Institute of State and Local Government at Claremont McKenna College, observing that the Central Valley's population has jumped an estimated 20 percent since 2000, called the greater Valley area between Chico and Bakersfield "now short on representation," but added that coastal regions would likely resist losing a seat.

"None of us have a clue, frankly, what the districts are going to look like," acknowledged Rep. Jim Costa, D-Fresno.

There will, however, be plenty of data to keep political junkies busy.

The 2010 census cost $13 billion, several billion dollars over budget and a record sum for the decennial headcount. Overall, auditors and investigators praise the complex undertaking while also citing shortcomings.

"An operationally successful Census was no small accomplishment," auditors with the Government Accountability Office noted this month, adding that "at the same time, the (Census) Bureau had to overcome a variety of internal management challenges."

The nonpartisan GAO auditors gave a similarly nuanced, largely positive review to the Census Bureau's effort to reach hard-to-count populations including minorities and immigrants. The auditors called the outreach efforts imperfect but "generally more robust" than in 2000, with more census advertising and more foreign languages spoken by enumerators.

"Some degree of error in the form of persons missed, duplicated, or counted in the wrong place is inevitable due to the complexity in counting a large and diverse population," the GAO added in a Dec. 14 audit.

Much of the census work was done by temporary employees, including more than 1,000 hired for two Fresno offices whose responsibilities spanned the San Joaquin Valley and the Sierra Nevada.

The Fresno offices are now closed, but investigations continue into claims filed by former workers.

Walker, one of several Fresno-area workers to have filed similar civil rights complaints, says she encountered age and race discrimination before being fired. Her claim filed last year is still pending before the Equal Employment Opportunities Commission.

"The process is extremely slow," Walker said Friday, adding that "I am disappointed in the government's attempt at protecting its employees, temporary or otherwise, from discrimination."

Walker has retained Clovis-based attorney Brian Leighton, a former federal prosecutor who has frequently challenged government actions. Census Bureau officials have denied any wrongdoing.

Separately, the Commerce Department's Office of Inspector General has been investigating broader allegations about census operations within the San Joaquin Valley. In some cases, former workers have suggested tight deadlines and management pressures may have driven some enumerators to falsify data.

As a matter of policy, federal investigators do not discuss work in progress.

"The investigation is ongoing," Walker said Friday. "I know former (Census Bureau) employees have received requests for information as recently as November."